It is standard in airports or shopping centers to provide luggage or shopping carts that can only be used by authorized persons having the appropriate card or token. The token or card can be returned to the user once the card is itself returned to the appropriate station. The system is intended to prevent unauthorized persons from using the carts, and ensures that the authorized users will return them to the depot.
Thus as described in my copending application Ser. No. 07/985,676 filed Dec. 4, 1992 and now abandoned, the system comprises a latch member that is pivoted by a chain or cable on a fixed support or another cart and a lock having a slot into which the member can be fitted and in which it is retained until the right token or card is inserted into a slot of the lock. The token or card can only be recovered by the user when a latch member is reinserted into the lock, so that the user must return the cart to the depot in order to recuperate his token or card. Such arrangements are fairly complex, requiring that the token or card be evaluated so that a latching mechanism can be operated. In general they are too complex for use merely to ensure that a cart is returned to the storage depot.